The UK Passport Agency have announced price rises from 5th October. This is no doubt due to the new database structures resulting from the ID card white elephant.
By renewing before then people will not only save themselves some money, but can avoid the ID card database fiasco for a further 10 years.

My passport expires in 2008, but I'll be renewing in september, the loss of a couple of years is paid for by the saving - this is quite apart from the issue of protesting against an ineffectual scheme (ID cards can't tell anyone about acts which have yet to be committed - and they give a false sense of security).

The No2ID site has a press release upon the price rises. They also have a history of price rises since Labour came to power (the last price should actually be £66):

March 1998 - £3 (17%) rise to £21

December 1999 - £7 (33%) rise to £28

January 2002 - £2 (7%) rise to £30

November 2002 â€“ £3 (10%) rise to £33

October 2003 â€“ £9 (27%) rise to £42, over half claimed to be for anti-fraud measures including microchips & biometrics and also to pay off its £26m debt to the Treasury for the 1999 computer crisis - see http://news.bbc.co.uk/1/hi/uk/3078483.stm

After October 2006 â€“ expect another price rise of around 35% to £69*, again claiming anti-fraud measures as well as establishment of NIR. Note the first fingerprinting trials are still not expected until 2007 at the earliest. Current "biometrics" are, in fact, nothing more than measurements derived from the scanned photograph, stored as a "facial geometry template".

Further rises are expected, from the 'Renew' campaign FAQ:

Q. Isn't renewing a waste of money?

We reckon that if you renew your passport in the ordinary way and it has up to EIGHT years to run, you will be financially ahead for all that time. When the price rises to the government estimate of £93, that'll be £42 (80%) more than it costs now. A ten year passport: £51 - Ten years of freedom: priceless.